Hi folks,
I have a need to capture the exact headers sent by a client. The problem
is I also use options forwardfor and http-server-close, so the headers
sent to my backend are altered by HAProxy.
My plan is to copy any affected headers under new names, using a special
prefix. This way my backend application has a way to differentiate
between modified headers and original headers. HAProxy doesn't seem to
have a command for copying headers. There is only reqadd for adding and
reqrep for replacing. However, I can fake a copy by injecting a newline
in the middle of a replacement value:
reqirep ^(Connection:)(.*) Connection:\2\nOrig-\1\2
If the client provides:
Connection: Keep-Alive
Then the above rule (along with http-server-close) will cause HAproxy to
send the request with:
Connection: Keep-Alive
Orig-Connection: Keep-Alive
Connection: close
My backend application can then be configured to capture the Connection
header only if it is prefixed.
This seems to work, but I am posting to the mailing list first just to
confirm if this isn't an abuse of reqirep.
Thanks,
Justin
